The invention relates to an energy storage unit, in particular a battery module, having a plurality of galvanic cells, in particular of battery cells, wherein the galvanic cells in each case have a first outer side comprising a first electrode and a second outer side comprising a second electrode and the galvanic cells are electrically interconnected with one another by juxtaposition of the galvanic cells by way of the outer sides via the electrodes. Consequently, the invention generally relates to the interconnection of galvanic cells, in particular of battery cells, to form a multi-cell energy store.
Furthermore, the invention relates to a battery cell for use with an energy storage unit of this kind, and to a method for producing a battery cell of this kind.
Such energy storage units and battery cells are usable in particular as mobile energy storage units or energy storage units used in a stationary fashion.
In order to be able to provide energy storage units which are designed to supply high voltages and/or high currents, it is known for a plurality of individual cells to be electrically interconnected in series or electrically interconnected in parallel to form an energy storage unit. For interconnecting a plurality of individual cells to form an energy storage unit, different techniques are known in the prior art, wherein these different interconnection techniques occasionally require different designs of the galvanic cells to be interconnected.
By way of example, so-called pouch cells, for the electrical contacting, usually have thin metal strips or metal foils as so-called “contact lugs”. Such pouch cells are known in the prior art for example from the document DE 10 2010 032 414 A1 or the document EP 2 413 414 A3. In this case, a series or parallel connection of such pouch cells is usually produced by contacting the contact lugs by means of soldering, screw or crimp connections, as disclosed for example in the document EP 2 605 301 A2.
Prismatic battery cells surrounded by a so-called hard case usually have so-called cell terminals for the electrical contacting, said cell terminals projecting from the hard case. Said cell terminals are usually electrically connected to one another for the interconnection of a plurality of such prismatic cells by means of so-called cell connectors by screw or welding connection.
The document U.S. Pat. No. 8,372,536 B2 and the document DE 10 2012 221 680, not yet published on the filing date of this invention, additionally disclose battery cells having a metal housing, wherein a part of the metal housing is designed as a cell terminal of the battery cell, such that battery cells designed in this way are electrically contactable with one another by juxtaposition.
Alongside the interconnection of galvanic cells to form an energy storage unit, a further challenge is to provide safety measures in order to be able to ensure safe operation of the energy storage unit. One safety measure, which additionally counteracts premature aging of the galvanic cells, is to regulate the temperature of the galvanic cells of an energy storage unit. For this purpose, a cooling plate through which coolant flows and on which the galvanic cells are arranged is usually used as a cooling device. Disadvantageously, such a cooling plate results in an increase in weight, which is undesired particularly in automotive engineering.
As further safety measures, the document EP 2 605 301 A2 discloses, for example, so-called thermal safety barriers that are used between galvanic cells arranged alongside one another. Said safety barriers, in the case of so-called thermal runaway of a galvanic cell, are intended to prevent the thermal runaway from being transmitted to adjacent galvanic cells and thus resulting in a chain reaction that destroys a multiplicity of galvanic cells as a consequence.
Against this background it is an object of the invention to improve an energy storage unit, in particular a battery module, having a plurality of galvanic cells, in particular battery cells, in particular to the effect that the weight of the energy storage unit is reduced, particularly with regard to the ratio of “passive mass” (cell connectors, cell housings, safety devices, etc.) to “active mass” (cathode material, anode material, solvents, etc.). Furthermore, in particular the number of components of the energy storage unit is intended to be reduced, and thus the production of an energy storage unit is intended to become advantageously more cost-effective.
In addition, the number of manufacturing steps required for producing an energy storage unit is advantageously intended to be reduced.